“Poor @OMAROSA,” Mr. Olbermann tweeted to his more than one million followers. “Offended when asked about Trump, same day as UVA Nazi rally. She had never realized that her only relevance is as Trump’s pet.”

Poor @OMAROSA. Offended when asked about Trump, same day as UVA Nazi rally. She had never realized that her only relevance is as Trump’s pet https://t.co/1HPzTt8oyG

Mr. Olbermann, a former CNN host, was referring to Ms. Manigault’s controversial appearance at the National Association of Black Journalists conference in New Orleans Friday — the same day that torch-bearing white supremacists marched through the University of Virginia campus to protest the removal of Confederate Gen. Robert E. Lee from Charlottesville’s Emancipation Park.

Nabila Haniss, who frequently appears on A&E’s “Storage Wars,” said people like Mr. Olbermann are deepening the racial divide in America.

“@KeithOlbermann is exactly what’s wrong with this country!” she wrote in response to Ms. Manigault. “He and his ilk is what’s causing the divide! So disrespectful!”

Several activists were photographed Friday turning their backs to Ms. Manigault as she spoke on a panel about police brutality at the National Association of Black Journalists conference. Her ties to the Trump administration were a point of contention among the other panelists and audience members.